


Code: Katrina

by PhoenixReign



Category: Code Lyoko
Genre: Adventure, Family, Friendship, Lyoko, Science Fiction, code, warriors - Freeform
Language: English
Status: In-Progress
Published: 2020-06-26
Updated: 2020-06-27
Packaged: 2021-03-03 19:42:14
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 4
Words: 3,689
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24920989
Author URL: https://archiveofourown.org/users/PhoenixReign/pseuds/PhoenixReign
Summary: Ulrich's sister, Katrina went missing five years ago.  What happens when Jeremie and Aelita discover that there's another person on Lyoko? Could it be Katrina? Or will Ulrich's hope of reuniting with his sister be in vein?
Kudos: 1





	1. Chapter 1

It was an average day in the Stern residence. Katrina who was the eldest child was sitting in her room studying for her high school exams. She was a senior so passing these exams were important to her. Books were scattered across her desk with papers in between. She was completely focused until a knock on her door brought her back to reality. The door opened revealing her younger brother.

"Ugh what do you want Ulrich?" She asked annoyed with being interrupted during her study session.

"Can you help me with my pencak silat training?" He asked. Katrina was a brown belt while Ulrich was just a beginner. Because of this, Ulrich often asked his older sister to help him with his training. Unfortunately, he always asked during the most inconvenient times like this one.

"I'm busy" She responded refocusing on her studies.

"What a surprise" Ulrich muttered sarcastically before leaving closing the door behind him. Katrina heard him and simply rolled her eyes in response. Now it was dinner time. As much as Katrina claimed she wasn't hungry, her father insisted she eat with the family.

"Ulrich, care to explain why you're still failing math?" Their father questioned sternly as he wiped his face with his napkin.

"Because it's hard" Ulrich simply replied not making any eye contact with his father.

"This is unacceptable Ulrich" He stated giving his son a serious look even though Ulrich was looking down at his plate. "Katrina you seem to be doing well in math. From now on I want you to tutor your brother" He continued turning to his daughter.

"Yeah, that's not happening" She stated as she stabbed a bite of food with her fork and ate it.

"Trina I wasn't asking" Their father noted.

"I have my own studying to do. I got exams coming up" She argued.

"You're a straight A student and Ulrich is failing" he stated in response.

"Oh, so I have to drop what I'm doing to tutor someone who can't be bothered to study on his own" She said annoyed with her father.

"Trina dear calm down" Her mother chimed sensing her daughter's frustration. She then turned to her husband. "Honey I don't think it's fair to have Trina tutor Ulrich when she has plenty of studying to do on her own" She said trying to reason with him.

"Fine then, if Ulrich fails again then they're both grounded" he announced. Katrina choked on her drink that she just sipped.

"What? You're kidding right?" She questioned in disbelief.

"Since you refuse to tutor your brother, you get punished as well" he explained. Frustrated with her father, Katrina got up from her seat throwing her napkin on the table and stormed away. The rest continued eating in silence. Ulrich felt pressured now. He had to pass his next math test, or not only will he get in trouble, but his sister as well.

Later that night Ulrich was up in his room. He sat on his bed with his math textbook in his hands and a notebook sitting next to him. There was a knock on the door and Katrina entered his room.

"Hey, can we talk?" She asked. Ulrich turned off the Subdigital music he had playing. Katrina walked in the room and sat at his desk chair.

"I'm sorry you got dragged into this Nina" Ulrich said. Nina was how Ulrich used to pronounce his sister's name when he was younger and could barely talk. Now it was just a nickname that only he referred to her as.

"Listen, I'm going to make a deal with you" She told him.

"What kind of deal?" he asked.

"You know how you always ask me to help you with your pencak silat training?" She inquired. Ulrich has a vague idea of where she was going with this.

"Yeah" he responded.

"Alright, well if you pass your next math test with at least a C I will spend the day giving you a pencak silat lesson" She offered. Ulrich's eyes lit up, yet he was still somewhat skeptical.

"You promise?" He questioned. She would always say she would, but they usually wind up being empty promises. Katrina nodded her head. She was probably only doing this because she would get mad at him if she got grounded because of him. Still, it gave him more motivation to study.


	2. Chapter 1

During the summer Katrina decided to do an internship at a local computer laboratory. She worked there five days a week for only 4 hours. One day she didn't return home. Her mother called her cell phone, but she never picked up. She then called the lab. The person on the other end claimed that they didn't know where she was. Her parents panicked calling the police to report her missing. The police conducted an investigation that eventually turned cold. The Stern family feared they would never see Katrina ever again.

Five years later Ulrich was now boarding at Kadic Academy. He was hanging out flipping through an old scrap book that his sister made of them years ago. His roommate Odd entered the room after walking his dog Kiwi.

"Hey Ulrich, whatcha got there?" Odd asked noticing the book he was flipping through.

"An old scrapbook my sister gave me" He answered with somber tone in his voice.

"I didn't know you have a sister. How come you never mentioned her before?" Odd questioned.

"It's a difficult subject to talk about. You see, she went missing five years ago after she started this internship at some computer lab in town" Ulrich explained. Odd then sat on Ulrich's bed looking over taking a glance at the book seeing a picture of Ulrich and his sister.

"Hey your sister's pretty" Odd commented. In another room Jeremie was on his computer with Aelita sitting on his bed with her laptop. He was running some codes while Aelita was monitoring Lyoko. Something came up on Aelita's screen. It was data of something unknown going on Lyoko.

"Hey Jeremie, take a look at this" Aelita told him as she got up and showed him what was on her screen. Jeremie seemed perplexed by this.

"Hmm that's strange. Don't think I've seen that before" He stated. He decided to download the information from Aelita's laptop onto a disc so he can upload it onto his computer. He examined the information then suddenly an activated tower appeared.

"There's an activated tower in the Desert sector" Jeremie stated.

"I'll call Yumi" Aelita announced. As Aelita was dialing Yumi's number the tower deactivated.

"Wait the tower just deactivated" Jeremie told her. Aelita was confused by this.

"by itself?" She questioned.

"Looks like it" He responded.

"We have some free time before class. Should we head to the factory and check it out?" Aelita suggested.

"Yeah that sounds like a good idea" Jeremie replied. The two head to the factory. Once there Jeremie sets himself up at the super computer and checks out what's happening on Lyoko.

He noticed that there were monsters in the desert section that were being destroyed by something, but he couldn't pin point what it was. He did some data mining and discovered that there was another person on Lyoko. They couldn't tell who the person was exactly. Just that it was in fact a person.

"How on earth did someone get virtualized onto Lyoko without us noticing?" Jeremie mumbled to himself as he continued typing.

"Do you think that person is responsible for deactivating the tower and destroying all those monsters?" Aelita questioned.

"Possibly" Jeremie responded.

"Shall I go to Lyoko and see if I could find this person?" She asked.

"No, it's too risky without the others here" He replied. "Although this person is incredible. They deactivated a tower before XANA had the chance to launch an attack" he then commented.

"So what should we do?" She questioned.

"You go back to the academy. Let the others know what's going on. I'll stay here and see if I could get more information" He responded. Aelita nodded and headed back to the academy. She met up with the others in the cafeteria and explained to them what her and Jeremie discovered.

"What? There's another person on Lyoko? How is that possible?" Yumi questioned.

"We have no idea yet. Before a tower was activated and it seems that this person deactivated it before XANA could attack" Aelita stated.

"But how come we've never noticed them before? Lyoko isn't exactly that big to not notice" Yumi questioned.

"We don't know. Jeremie is at the factory finding that out right now" She answered. Odd was busy scarfing down his lunch and Ulrich just sat there in silence.

"Is everything okay Ulrich?" Aelita then questioned.

"Peachy" He replied slightly mopey.

"He's been staring at a scrapbook all day cause he misses his sister" Odd chimed with a mouth full of food.

"I didn't know you had a sister" Yumi commented looking at Ulrich.

"I don't want to talk about it" Ulrich stated.

"Are you and your sister close?" Aelita asked.

"Not really, it's complicated" Ulrich answered.

"You should see the picture he has of her. She's too pretty to be related to a guy like Ulrich" Odd commented with a laugh.

"Shut up Odd" Ulrich said with a growl.

"Let's hope that she's not as gloomy as you are" Odd commented as he continued to eat. After lunch was over the group headed to class. Jeremie decided to skip class to figure out who this person was and how they got on to Lyoko.


	3. Chapter 2

Jeremie and Aelita were back in at the factory trying to figure out who this mystery person on Lyoko was. So far after hours of data mining all they could find out was that it was a girl that carried similar codes to Aelita meaning she could deactivate towers and have access to the information in Sector Five. There wasn't much more information on the girl. Later that day Jeremie decided that he wanted to see if he could find this girl on Lyoko. He told the others to meet him at the factory for an important mission.

"So, what's this all about Einstein?" Odd questioned

"We're going to find this girl that's somewhere on Lyoko" Jeremie stated.

"Do you know where she is exactly?" Yumi asked.

"She's still somewhere in the desert section" He responded. The group minus Jeremie was virtualized onto Lyoko in the desert section. At the moment it seemed pretty vacant. No girl and no monsters. It would make sense that there were no monsters since there was no activated tower. However, the desert section was a pretty open place and fairly small so there should be really no trouble spotting a person. That was if they weren't hiding out in a tower.

"Jeremie, do you have an exact location on where she is?" Ulrich asked. "We don't see anyone here" He then added.

"Hold on, give me a moment" Jeremie spoke as he tried to pin point her location. "According to the data on the map she's Southeast from where your location" He then answered after finding her exact location. "She's currently on the move though so you better hurry" He added noticing that her icon was moving on the screen.

"You mind sending us some vehicles?" Odd requested. Jeremie did as requested and sent them their vehicles. "Hey Ulrich, imagine if this mystery girl turns out to be your sister" Odd joked.

"Shut up Odd that's not funny" Ulrich stated in no mood for his jokes.

"Oh, lighten up will ya" Odd responded then moving ahead of him. Then soon an activated tower appeared on Jeremie's screen. Luckily it was located in the desert sector.

"Guys forget about the girl for now. A tower just activated west for where you guys are now" Jeremie announced. The group abandoned their mission and headed straight for the activated tower. "There's a swarm of hornets and a group of crabs heading your way" Jeremie warned noticing the monsters appearing on the screen. Odd managed to take out two hornets with his laser arrows and Ulrich defeated one crab. Yumi focused on getting Aelita to the tower while blocking attacks with her fan. Then suddenly several of the hornets were taken out at once. Odd had caught up to Yumi and Aelita so they thought it was him who did it.

"Well done Odd" Aelita praised.

"That wasn't me" Odd responded confused to who took out the hornets himself.

"Well it wasn't me or Ulrich. I wonder who did it?" Yumi questioned confused.

"Look ahead of you. It's the mystery girl" Jeremie voiced. The group looked head and sure enough, there she was. She was tall with brown hair that was pulled into a bun with her bangs hanging loose and a black headband that matched the black and green suit she was wearing with silver armor around her chest. She leaped over a crap shooting it in the target with her laser pistol causing the crab to explode. Ulrich immediate recognized the girl. Odd was right, it was his sister.

"I don't believe it. Odd was right. It is her" Ulrich commented in disbelief after joining the others.

"What? I was kidding. I didn't think it would actually be her" Odd noted. After she defeated the crab, she ran into the tower to deactivate it.

"I'll say, she has impeccable timing. She's deactivating towers before XANA is able to launch an attack" Jeremie stated. After the tower was deactivated, she exited the tower and was greeted by the group.

"Umm hello. Who are you guys?" She asked.

"Nina...?" Ulrich called out to see if it was really her or if XANA was playing a trick on him. The girl seemed surprised by that name.

"The only person that calls me that is my little brother Ulrich" She stated in shock. Ulrich then ran up to her giving her a hug.

"It really is you Nina" He said as he embraced her. That's when she realized that it was Ulrich. She returned the hug after it hit her that he was her brother.

"I missed you little brother" She mumbled to him. The two pulled apart. "Sorry, I should probably introduce myself. I'm Katrina Stern, some people call me Trina and only this one calls me Nina" She said as she placed her hand on her brother's head. The group introduced themselves to her and explained to Katrina what was going on. Ulrich was happy that after five years apart, he was finally reunited with his sister. The only problem was that she was stuck here on Lyoko.


	4. Chapter 3

After the tower was deactivated the group was devirtualized leaving Katrina on Lyoko all by herself. Ulrich was happy to finally be reunited with his sister after being apart for five years but was saddened to leave her alone on a virtual world.

"Do you think Code Earth will work on Nina?" Ulrich asked. Jeremy shook his head.

"Code Earth was designed specifically for Aelita. I would have to reprogram it using Katrina's DNA, but even then, it most likely wouldn't work. There are too many bugs in the program. She could wind up lost forever" Jeremie explained. Ulrich didn't like the sound of that. It was bad enough that she disappeared in the first place. Now there was a possible chance she might disappear forever. Ulrich balled his hands into a fist in frustration.

"It's okay Ulrich. We'll find a way to get Katrina back" Yumi reassured him placing her hand on his shoulder. Later that day, they all went to class. Jeremie, Ulrich, and Odd were in Miss Hertz's class. Ulrich was too distracted by the situation with his sister to pay attention to the lesson.

"Ulrich!" Miss. Hertz called on him.

"Huh?" He responded coming out of his daze.

"What's the answer to the question on the board?" She asked. Ulrich examined the question on the board. After some thought he couldn't come up with an answer.

"Uh......I don't know" He said giving up.

"Well maybe if you paid attention you would know" She stated sternly with a slight glare. She went back to teaching as she explained the answer to the question on the board.

"Hey, no need to be so glum. Jeremie said he was going to re-work the program later after school" Odd whispered to him.

"Uh huh" He responded not really paying attention. The bell rang dismissing the class. Ulrich went straight to his dorm not in the mood to be around other people. They just let him be for now. Odd and Jeremie went to the cafeteria to meet up with Yumi and Aelita, who were already sitting at the table eating their lunch. They got their food and sat down at their table.

"Where's Ulrich?" Yumi asked.

"He decided to go sulk alone" Odd replied.

"I guess he's really close to his sister since he's so upset" Aelita commented.

"Yeah he seemed so happy to finally see her again after being apart for five years" Yumi chimed.

"If I manage to get a hold of a sample of Katrina's DNA, I should be able to re-program Code Earth to work devirtualize her." Jeremie mentioned.

"How are we going to do that? It's not like Ulrich could just go home and find something in her room that would have any of Katrina's DNA on it" Odd commented.

"Wait, isn't Katrina's DNA already in the computer? Why can't we use that?" Aelita questioned remembering seeing Katrina's DNA sequence on the screen the other day.

"I might be able to use it if it's not corrupted by a virus, I'd like to get a backup sample just in case. If I use the same program I used to materialize Aelita's DNA, I should have no problem materializing a sample of Katrina's" He explained.

"So, are we going to head to the factory?" Yumi questioned.

"No not yet. I'll let you guys know once I'm done" Jeremie said. He finished his lunch and got up from the table. He threw out his garbage and headed to his dorm. Aelita met up with him after she finished.

The two were in Jeremie's dorm trying to figure out a way to materialize Katrina. Jeremie sat at his computer while Aelita sat on Jeremie's bed with the laptop. Jeremie tried to contact Katrina using the same method he used when Aelita was in her situation. Soon enough Katrina's face popped up on his screen.

"Hi, you must be Jeremie. It's nice to put face to voice" Katrina greeted with a soft smile.

"You know, you look nothing like Ulrich" Jeremie commented.

"Thanks for the compliment." She responded. Aelita placed the laptop down on the bed and got up from the bed walking over to the computer.

"How close were you and Ulrich before you got stuck on Lyoko?" Aelita asked.

"Well we had a typical sibling relationship. We fought a lot of little things, but for the most part we got along fine" She answered.

"Do you remember how you got stuck on Lyoko?" Jeremie asked. Katrina shook her head.

"No before I got here, I was an intern at a computer lab that was funded by the government" She told him.

"Do you remember who was in charge of the lab?" He asked. Katrina shrugged her shoulders.

"I'm not too sure, but I think his name was Dr. Franz Hopper or something" She replied. Both Jeremie and Aelita seemed surprised by this. Katrina used to work with Aelita's father.

"Well we just got our answer. Franz Hopper is the one who created Lyoko" Jeremie told her.

"He's also my father" Aelita mentioned.

"Oh, you're the daughter Dr. Hopper used to talk about. He mentioned that his goal was to create a world where he could keep his family safe" Katrina stated.

"Anyways, we're going to try and find a way to rematerialize you back on Earth. We need a favor from you though" Jeremie told her.

"What is it?" She asked.

"I need you to go to Sector Five and retrieve some data for me" Jeremie stated.

"Sector Five? I've never heard of that sector before. I only know of Forest, Desert, Ice, and Mountain sectors" She commented.

"Maybe I should go to Lyoko and take her there" Aelita suggested looking at Jeremie.

"It would be too risky for you to go by yourself" He noted.

"Excuse me, but I think I'm more than capable of acting as someone's escort" Katrina commented feeling offended.

"Well if you lose all your life points, you'll disappear forever" Jeremie mentioned.

"Yes, I'm well aware of that" Katrina commented.

"We could at least bring Ulrich. He's been acting all depressed since our last trip to Lyoko" Aelita then suggested.

"Ulrich is always like that though. I haven't seen my brother in a good mood since he started middle school" Katrina mentioned. "My father is partially to blame though if I were to be honest. He's always so hard on Ulrich especially when it comes to academics. If Ulrich got so much as a C on his report card, he was grounded, and I usually would be the one stuck tutoring him and if I refused, I would also get punished" She continued.

"That explains why he's so reluctant to go home" Aelita chimed.

"Anyways, I guess we could wait for Ulrich. I mean since I don't exactly know what to do in this Sector Five area it would make sense to have someone else there as back up" Katrina stated.

"Alright then, well do this tomorrow. I'll let Ulrich know what's going on" Jeremie stated.

"Okay, I'm gonna go, I think I hear some movement outside. I'm gonna go check it out" Katrina said before ending the video transmission.

"Do you think Ulrich is going to be up for it?" Aelita questioned.

"It involves his sister, so I don't see why not" He responded. Jeremie went back to re-coding the program after Aelita said her goodbyes and left for the night.


End file.
